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# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Live value resolution.
Live values are extracted from the known execution context.
Requires activity and reaching definitions analyses.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import gast
import six
from tensorflow.python.autograph.pyct import anno
from tensorflow.python.autograph.pyct import transformer
# TODO(aqj): Do we need this? Do other builtins fail in similar ways
# See b/114389775 for a related bug in pyct
# These symbols are legal in Python, but don't appear in the namespace.
_SPECIAL_SYMBOLS = {'range': range, 'print': print}
if six.PY2:
_SPECIAL_SYMBOLS['xrange'] = xrange
class LiveValueResolver(transformer.Base):
"""Annotates nodes with live values."""
def __init__(self, context, literals):
super(LiveValueResolver, self).__init__(context)
self.literals = literals
def visit_ClassDef(self, node):
self.generic_visit(node)
anno.setanno(node, 'live_val', self.entity_info.namespace[node.name])
return node
def visit_Name(self, node):
self.generic_visit(node)
if isinstance(node.ctx, gast.Load):
defs = anno.getanno(node, anno.Static.DEFINITIONS, ())
is_defined = bool(defs)
has_single_def = len(defs) == 1
if not is_defined:
if node.id in self.literals:
anno.setanno(node, 'live_val', self.literals[node.id])
elif node.id in self.entity_info.namespace:
obj = self.entity_info.namespace[node.id]
anno.setanno(node, 'live_val', obj)
if hasattr(obj, '__name__'):
anno.setanno(node, 'fqn', (obj.__name__,))
elif hasattr(obj, '__class__'):
obj_class = obj.__class__
anno.setanno(node, 'fqn',
(obj_class.__module__, obj_class.__name__))
else:
# If the symbol value is for example a primitive, then it will not
# have a name.
pass
elif node.id in _SPECIAL_SYMBOLS:
# Note: if the user redefined any of these symbols, then they would
# be visible in the namespace and we would never reach this branch.
anno.setanno(node, 'live_val', _SPECIAL_SYMBOLS[node.id])
else:
pass
# TODO(mdan): Should we raise an error here?
# Can encounter this when:
# * a symbol truly lacks reference
# * a symbol is new, like the new name of a function we just renamed.
else:
pass
# TODO(mdan): Attempt to trace its value through the local chain.
# TODO(mdan): Use type annotations as fallback.
if has_single_def:
def_, = defs
# Note: param_of is a weakref.
if def_.param_of and def_.param_of() is self.enclosing_entities[0]:
if node.id in self.entity_info.arg_values:
obj = self.entity_info.arg_values[node.id]
anno.setanno(node, 'live_val', obj)
anno.setanno(node, 'fqn', (obj.__class__.__name__,))
return node
def visit_Attribute(self, node):
self.generic_visit(node)
if anno.hasanno(node.value, 'live_val'):
assert anno.hasanno(node.value, 'fqn')
parent_object = anno.getanno(node.value, 'live_val')
anno.setanno(node, 'parent_type', type(parent_object))
anno.setanno(node, 'fqn', anno.getanno(node.value, 'fqn') + (node.attr,))
if hasattr(parent_object, node.attr):
# This can happen when the attribute's creation and use depend on the
# same static condition, for example:
#
# if cond:
# foo.bar = baz
# if cond:
# x = foo.bar
#
anno.setanno(node, 'live_val', getattr(parent_object, node.attr))
# TODO(mdan): Investigate the role built-in annotations can play here.
elif anno.hasanno(node.value, 'type'):
parent_type = anno.getanno(node.value, 'type')
if hasattr(parent_type, node.attr):
# This should hold for static members like methods.
# This would not hold for dynamic members like function attributes.
# For the dynamic case, we simply leave the node without an annotation,
# and let downstream consumers figure out what to do.
anno.setanno(node, 'parent_type', parent_type)
anno.setanno(node, 'live_val', getattr(parent_type, node.attr))
anno.setanno(node, 'fqn',
anno.getanno(node.value, 'type_fqn') + (node.attr,))
elif isinstance(node.value, gast.Name):
# TODO(mdan): Figure out what to do when calling attribute on local object
# Maybe just leave as-is?
pass
return node
def resolve(node, context, literals):
return LiveValueResolver(context, literals).visit(node)
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